Heat exchange element



Aug. 19, 1947. KRAMER HEAT EXCHANGE ELEMENT Filed March 19, 1943 INVENTOR.

Patented Aug. 19, 1947 2,426,107 HEAT EXCHANGE ELEMENT Nathan Kramer, Trenton,

Trenton Company, Trenton, N. J., a

Kramer N. J., assignor to corporation of New Jersey Application March 19, 1943, Serial No. 479,688

1 Claim.

This invention relates to a heat exchange element and, more including a tub particularly, to a structural part ular conduit and fins projecting laterally therefrom which is useful in radiators and the like.

An object of structure which the invention is to provide a fin is extremely simple and economical to manufacture.

Another object is to provide such a structure in which a plurality of fins are formed from a single piece of material tegral portions which in fixed spaced relationship,

structure, and t and are connected by inserve to maintain the fins to add rigidity to the improve the operative effect of the radiator or the like.

Another object is to provide such a structure which is so formed and arranged that a plurality of erative contact fins may be simultane ously associated in opand relationship with a tubular conduit in a simple and expeditious manner.

Another object is to provide such a structure which is adapted to be produced by a single pressing or stamping formed in exten after folded into fins suitable for duit.

or dieing operation and to be ed lengths which may be therea unitary plurality or group of association with a tubular congeneral eificiency of the structure enhanced.

A practical embodiment of the invention is shown in the accompanying drawing in which Fig. 1 represents a detail top plan view of an integral group of fins in operative association with a tubular conduit;

Fig. 2 represe shown in Fig. 1;

Fig. 3 represents an Fig. 4 represents a se nts a side elevation of the parts end view thereof;

ction of a strip of material which has been pressed, stamped or operated upon by a die to form the fins therein; and

Fig. 5 represents a perspective view of a unitary group of fins which has been folded from of material shown in the strip Fig. 4.

In this art, heat interchanging elements of radiators and the like commonly include a tubular conduit through which fluid is passed, and fins which are in contact with the exterior of the conduit and project laterally therefrom to act as radiating agents.

portant that the Among other things, it is imfins be maintained in fixed, predetermined spaced relationship with respect to a each other in o rder that radiation may be uniform, or substantially so, along the conduit; and that the structure have sufficient rigidity or permanency to allow for bending the conduit intermediate groups of fins without disturbing their proper cooperative positioning or relationship; as well as to insure durability of the structure when in use. It is likewise important, from the point of view of production costs, that the fins may be economically and expeditiously manufactured and associated with th a matter of importance that the structure be such as to attain and maintain a very high degree of efficiency without undue increase in its bulk or weight.

Referring now to the embodiment of the invention set forth in the drawings, the reference numeral 1 denotes a tubular, and in this instance circular, conduit composed of suitable material that is preferably metallic and heat conducting such, for instance, as copper or brass.

The conduit I carries a plurality of fins 2, which are also preferably composed of a heat conducting metal such as copper or brass. The fins 2, which are preferably substantially rectangular in form, as illustrated in Fig. 3, are all alike and are interconnected by bridges or straps 3 which are formed integral with the fins and alternately connect the latter at opposite sides as shown in Figs. 1 and 5. Any desired number of fins may be thus connected to form an integral group, which number will naturally vary according to the requirements of the product being manufactured.

Each fin is centrally pierced by a hole 4 of such size as to fit the outer circumference of the conduit I while permitting the fins to be mounted on the conduit by sliding them thereon. This association of fins and conduit may be made rigid or fixed in several ways as, for instance, by forming the hole in the fin slightly smaller than the conduit and then associating the parts after heating the fin and chilling the conduit; or by forming the hole in the fin slightly smaller than the conduit, then distorting the periphery of the hole to permit association of the parts, and then restoring the'distortion; or by expanding---the conduit by hydraulic or mechanical means after the parts are associated; or by fusing the point of contact between the fin and conduit. If either of the last two procedures is followed, the hole may be formed slightly larger than the conduit to facilitate association. Other suitable ways of assembling these parts will doubtless occur to operators skilled in this industry, and it may be emphasized that the interconnection e conduit. And again it is of the individual fins by the bridges or straps 3 tends to maintain a group of fins in fixed position on the conduit because the accidental or unintentional movement of any fin for even a very short distance along the conduit will at once cause its connection with the adjacent fin to cramp the latter angularly upon the conduit and thereby prevent further movement. This results primarily from the fact that the fins are interconnected at only one side as distinguished from a connection at both sides.

The conduit I may, of course, be formed in any well known or approved manner which it seems wholly superfluous here to exemplify. As to the fins, I prefer to form them from a strip or ribbon of sheet metal 5 which is first passed through suitable pressing devices, such as a pair of cutting rollers, which form the holes 4 and, intermediate the holes, form similar openings 6. 6 connected by a slit 1. Immediately after the said holes, openings and slits have been formed in the strip 5, and preferably in a continuous operation, the strip may be fed between a pair of dies which fold the same into the zig-zag formation well represented in Fig. 5, and also shown in Fig. 1. In this dieing operation, portions of the strap adjacent the openings 8, 6 are bent along the broken lines 9, 8 so as to form wings 8, O projecting laterally from and in the same plane with the fins 2, which wings increase the radiating efficiency of the fins.

As such roller and die operations are well understood in the metal forming industry, it is regarded as unnecessary further to detail the same herein: and it should also be noted that any other suitable procedure for forming the fins may be followed.

The length of the strip 5 will be fixed in accordance with the predetermined number of fins to be formed as an integral unit, and such units may be located in spaced relationship on the conduit I, if desired, so as to permit the latter to be bent intermediate groups of fins in order 4 to change its course to conform with the design of the radiator or the like in which this heat exchange element is to be incorporated.

The bridges or straps 3 have not only the function hereinabove mentioned of preventing dislodgment of a group of fins from predetermined position on the conduit, but they also serve accurately to space the fins in order to, promote uniformity of radiation, and materially increase the rigidity of the fin structure so as to obviate the necessity of employing separate elements to interconnect the fins, thereby leading to a substantial economy in both material and labor.

It will be understood that various changes may be resorted to in the form, construction, arrangement and material of this invention, and in the procedure followed in its manufacture, without departing from the spirit and scope of my invention; and hence I do not intend to be limited to the details herein shown and described except as they may be included in the claim.

What I claim' is:

A heat exchange element including a plurality of integrally connected fins, each fin being connected at the top and bottom of one edge with the fin at one side thereof and at the top and bottom of another edge with the fin at the other side thereof, said fins having wings projecting between and beyond the points of interconnection and lying in the same planes as the fins.

NATHAN KRAMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,744,074 Gortner Jan. 21, 1930 2,173,666 Sibley Sept. 19, 1939 2,063,736 Hardiman et a1. Dec. 8, 1936 1,460,772 Todd July 3, 1923 

